Filter cartridge with integrated gaseous seal for multimodal surgical gas delivery system

ABSTRACT

A system is disclosed for delivering gas during a laparoscopic surgical procedure performed within a patient&#39;s abdominal cavity which includes a gas delivery device having a housing with a port for receiving pressurized insufflation gas from a gas source, a pump assembly for circulating gas throughout the system, and a separate gas conditioning unit configured for operative association with the gas delivery device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application in a continuation-in-part of co-pending U.S.application Ser. No. 14/609,952 filed Jan. 30, 2015, the disclosure ofwhich is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention is directed to laparoscopic surgery, and moreparticularly, to a filter device for a multimodal insufflation systemused during laparoscopic surgical procedures.

2. Description of Related Art

Laparoscopic or “minimally invasive” surgical techniques are becomingcommonplace in the performance of procedures such as cholecystectomies,appendectomies, hernia repair and nephrectomies. Benefits of suchprocedures include reduced trauma to the patient, reduced opportunityfor infection, and decreased recovery time. Such procedures within theabdominal (peritoneal) cavity are typically performed through a deviceknown as a trocar or cannula, which facilitates the introduction oflaparoscopic instruments into the abdominal cavity of a patient.

Additionally, such procedures commonly involve filling or “insufflating”the abdominal (peritoneal) cavity with a pressurized fluid, such ascarbon dioxide, to create what is referred to as a pneumoperitoneum. Theinsufflation can be carried out by a surgical access device (sometimesreferred to as a “cannula” or “trocar”) equipped to deliver insufflationfluid, or by a separate insufflation device, such as an insufflation(veress) needle. Introduction of surgical instruments into thepneumoperitoneum without a substantial loss of insufflation gas isdesirable, in order to maintain the pneumoperitoneum.

During typical laparoscopic procedures, a surgeon makes three to foursmall incisions, usually no larger than about twelve millimeters each,which are typically made with the surgical access devices themselves,typically using a separate inserter or obturator placed therein.Following insertion, the inserter is removed, and the trocar allowsaccess for instruments to be inserted into the abdominal cavity. Typicaltrocars often provide means to insufflate the abdominal cavity, so thatthe surgeon has an open interior space in which to work.

The trocar must provide a means to maintain the pressure within thecavity by sealing between the trocar and the surgical instrument beingused, while still allowing at least a minimum freedom of movement of thesurgical instruments. Such instruments can include, for example,scissors, grasping instruments, and occluding instruments, cauterizingunits, cameras, light sources and other surgical instruments. Sealingelements or mechanisms are typically provided on trocars to prevent theescape of insufflation gas. Sealing elements or mechanisms typicallyinclude a duckbill-type valve made of a relatively pliable material, toseal around an outer surface of surgical instruments passing through thetrocar.

SurgiQuest, Inc., Milford, Conn. USA has developed unique surgicalaccess devices that permit ready access to an insufflated surgicalcavity without the need for conventional mechanical seals, and it hasdeveloped related gas delivery systems for providing sufficient pressureand flow rates to such access devices, as described in whole or in partin U.S. Pat. No. 7,854,724.

The present invention relates to a multimodal gas delivery system andrelated devices for performing multiple surgical gas delivery functions,including insufflation, recirculation and filtration of insufflationfluids and gases. The use of a single multimodal system reducesoperating costs by requiring the purchase of only one system whileachieving multiple functions, and also thereby reduces the amount ofequipment needed in an operating room, thus reducing clutter andallowing space for other necessary equipment.

SUMMARY OF THE INVENTION

The subject invention is directed to a new and useful system fordelivering gas during a laparoscopic surgical procedure performed withina patient's abdominal cavity. The system includes, among other things, agas delivery device having a housing with a port for receivinginsufflating gas from a gas source. The gas delivery device includes apump assembly for circulating pressurized gas throughout the system. Thesystem further includes a disposable gas conditioning unit or cartridgeconfigured for operative association with the gas delivery device.

The gas conditioning unit includes a first internal flow path fordelivering pressurized gas delivered from the pump to an internal nozzleassembly configured to accelerate the pressurized gas and therebygenerate a continuous pressure barrier contained within the gasconditioning unit that inhibits egress of insufflation gas from theabdominal cavity. The gas conditioning unit further includes a secondinternal flow path for delivering insufflation gas to the abdominalcavity and for facilitating periodic static pressure measurements fromthe abdominal cavity, and a third internal flow path for returningdepressurized gas spent by the internal nozzle assembly back to the pumpunder vacuum.

The gas conditioning unit includes a generally cylindrical housinghaving a front end and an opposed rear end. The gas delivery unitincludes an engagement port for detachably receiving the rear end of thegas conditioning unit. The rear end of the gas conditioning unitincludes a rear cover having a first rear flow port corresponding to thefirst internal flow path, a second rear flow port corresponding to thesecond internal flow path, and a third rear flow port corresponding tothe third internal flow path. The front end of the gas conditioning unitincludes a front cover having a first front flow port corresponding tothe first internal flow path which communicates with a first conduit,and a second front flow port corresponding to the second internal flowpath which communicates with a second conduit.

The housing of the gas conditioning unit includes a pressure chamberlocated within the first internal flow path and communicating with thefirst rear flow port. The housing of the gas conditioning unit furtherincludes a central nozzle chamber having a cylindrical wall supportingthe annular nozzle assembly. The central nozzle chamber communicateswith the pressure chamber through an internal delivery port.

The annular nozzle assembly includes a cylindrical jet set having a pairof axially spaced apart outer sealing rings for sealingly isolating thenozzle assembly within the central nozzle chamber. The central nozzlechamber includes a plurality of circumferentially disposed spaced apartaxial fins distal to the cylindrical jet set for directing gas flow. Thecentral nozzle chamber communicates with a breathing tube proximal tothe cylindrical jet set that is open to atmosphere.

A first filter element is disposed within the pressure chamber forfiltering pressurized gas from the pump. The housing of the gasconditioning unit includes a diverter plate which interacts with therear cover to define a conditioning cavity disposed in the secondinternal flow path and configured to support a second filter element forfiltering insufflation gas from the gas source. The housing of the gasconditioning unit also includes a vacuum chamber located within thethird internal flow path.

The vacuum chamber communicates with the nozzle chamber through aplurality of gas transfer ports to permit spent gas from the nozzleassembly to return to the pump for repressurization and circulation. Athird filter element is disposed within the vacuum chamber for filteringdepressurized gas returning to the pump.

The housing of the gas conditioning unit further includes a reservoirchamber located within the third internal flow path, downstream from andin fluid communication with the vacuum chamber through a fluid transferport, for accommodating any fluid drawn into the housing of the gasconditioning unit by the pump. A fluid level sensor is arranged withinthe reservoir for detecting a predetermined fluid level therein.

The first conduit includes a fitting for communicating with a firstsurgical access port, and wherein the first access port includes amechanical valve associated with a central lumen thereof foraccommodating the introduction of surgical instruments into theabdominal cavity. The second conduit includes a fitting forcommunicating with a second surgical access port responsible forinsufflation and pressure measurement of the abdominal cavity.

The subject invention is also directed to a gas conditioning unit foruse with a gas delivery device during a laparoscopic surgical procedureperformed within a patient's abdominal cavity. The unit includes, amongother things, a housing having a rear end configured for engagement withthe gas delivery device and an opposed front end, a first filtered flowpath within the housing for delivering pressurized gas delivered fromthe pump to an internal nozzle assembly configured to accelerate thepressurized gas and thereby generate a continuous pressure barriercontained within the gas conditioning unit that inhibits egress ofinsufflation gas from the abdominal cavity, a second internal flow pathfor delivering insufflation gas to the abdominal cavity and forfacilitating periodic static pressure measurements from the abdominalcavity, and a third internal flow path for returning depressurized gasspent by the internal nozzle assembly back to the pump under vacuum.

These and other features of the surgical gas delivery system and the gasconditioning device of the subject invention and the manner in whichboth are manufactured and employed will become more readily apparent tothose having ordinary skill in the art from the following enablingdescription of the preferred embodiments of the subject invention takenin conjunction with the several drawings described below.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject inventionappertains will readily understand how to make and use the subjectinvention without undue experimentation, preferred embodiments thereofwill be described in detail herein below with reference to certainfigures, wherein:

FIG. 1 is an illustration of the operating environment in which the gasdelivery system of the subject invention is employed during alaparoscopic surgical procedure, which includes, among other things, agas delivery device having a housing with a port for receivingpressurized insufflation gas from a gas source, and a separate gasconditioning unit configured for operative association with the gasdelivery device;

FIG. 2 is a perspective view of the gas delivery device and separate gasconditioning unit illustrated in FIG. 1;

FIG. 3 is a perspective view of the gas conditioning unit of the subjectinvention as viewed from the front end of the unit, illustrating the twoconduits extending therefrom;

FIG. 4 is a perspective view of the gas conditioning unit of the subjectinvention as viewed from the rear end of unit, illustrating the threeflow ports thereof;

FIG. 5 is an exploded perspective view of the gas conditioning unit ofthe subject invention, with parts separated for ease of illustration;

FIG. 6 is an exploded perspective view of the annular jet rings whichform the internal nozzle assembly of the gas conditioning unit shown inFIG. 5;

FIG. 7 is a cross-sectional perspective view of the gas conditioningunit of the subject invention taken along line 7-7 of FIG. 3,illustrating the location of the filter elements within the housing ofthe filter unit;

FIG. 8 is a cross-sectional perspective view of the gas conditioningunit of the subject invention, taken along line 8-8 of FIG. 3,illustrating the internal features of the vacuum chamber within thehousing of the filter unit;

FIG. 9 is a cross-sectional view of the gas conditioning unit of thesubject invention, with a wall broken away to show the liquid levelsensing prisms in the reservoir;

FIG. 10 is a cross-sectional view of the gas conditioning unit of thesubject invention with a wall broken away to illustrate the insufflationand sensing path layout within the housing;

FIG. 11 is a cross-sectional view of the gas conditioning unit of thesubject invention with a wall broken away to illustrate the pressurepath layout within the housing;

FIG. 12 is a localized cross-sectional view of the central nozzlechamber within the housing; and

FIG. 13 is a cross-sectional view of the gas conditioning unit of thesubject invention with a wall broken away to illustrate the vacuum pathlayout within the housing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings wherein like reference numerals identifysimilar structural features or aspects of the subject invention, thereis illustrated in FIGS. 1 and 2, a new and useful system for deliveringand circulating medical gas (e.g., carbon dioxide) during a laparoscopicsurgical procedure performed within a patient's abdominal cavity.

The gas delivery system, which is designated generally by referencenumeral 10 includes, among other things, a gas delivery device 12 havinga housing 14 with a rear connector or port 16 for receiving pressurizedinsufflation gas from a gas source 18. As shown, the gas source 18 is aportable supply canister. However, it is envisioned that the medical orinsufflating gas could be supplied from another source, including forexample, a remote storage tank (e.g., house gas) as is well known in theart. A pump assembly 20 is enclosed within the housing 14 of deliverydevice 12 for circulating pressurized gas throughout the system 10 tomaintain a stable pneumo-peritoneum during a surgical procedure.

A graphical user interface 25 with associated control circuitry isprovided within the housing 14 of gas delivery device 12 for controllingthe operation of the pump assembly 20, as well as the delivery ofinsufflating gas from supply source 18. The interface and associatedcircuitry enables a user to readily adjust flow rates and supplypressures relating to the delivery, circulation and recirculation of gasand fluid throughout the system. The gas delivery system 10 furtherincludes a separate and preferably disposable gas conditioning unit 30,which is dimensioned and configured for operative association with thegas delivery device 12. As described in more detail below, the gasconditioning unit 30 is constructed in such a manner so that acontinuous gaseous pressure barrier is generated within the housing ofthe unit itself, remote from the patient. This gaseous pressure barrieror working zone prevents the egress of insufflation gas from theabdominal cavity of the patient while maintaining a stablepneumoperitoneum within the abdominal cavity. This feature differs fromthe multi-modal gas delivery systems disclosed in commonly assigned U.S.Pat. No. 7,854,724, wherein the gaseous pressure barrier is generatedwithin the housing of a specialized trocar at the surgical site.

The gas conditioning unit 30 includes a number of internal flow pathsconfigured to facilitate the periodic delivery of insufflating gas, aswell as the continuous circulation and recirculation of pressurized gas.In particular, a first internal flow path (i.e., the pressure path shownin FIG. 11) is provided for receiving pressurized gas from the pumpassembly 20 of the gas delivery device 12. The first internal flow pathis associated with a first conduit 32 that is connected to a firstsurgical access device or trocar 34. The trocar 34 is the primary pathfor introducing surgical instrumentation into the abdominal cavityduring a surgical procedure, and it has a mechanical seal installedtherein. The pressurized gas is used to create a pressure barrier withinthe gas conditioning unit 30 that prevents the egress of gas from theabdominal cavity by way of conduit 32. In doing so, it also maintains astable pneumoperitoneum within the abdominal cavity of the patient 15.

The gas conditioning unit 30 further includes a second internal flowpath (i.e., the sense/insufflation path shown in FIG. 10) for deliveringinsufflating gas from the gas delivery device 12 to the abdominal cavityof the patient 15 and for facilitating periodic static pressuremeasurements from the abdominal cavity by way of a second conduit 40connected to a second surgical access device or cannula 42. The durationof the insufflation interval between pressure measurements can vary,depending upon the patient and the operating environment. This flow andstop methodology for obtaining static pressure measurements from theabdominal cavity is well known in the art.

The gas conditioning unit 30 also includes a third internal flow path(i.e., the vacuum path shown in FIG. 13) for returning pressurized gasto the pump assembly 20 of the gas delivery device 12. The gas returnedto the pump assembly 20 is the spent pressurized gas that was used tocreate the pressure barrier within the conditioning unit 30.

With continuing reference to FIG. 2, the gas conditioning unit 30 isadapted and configured for ready installation into and removal from thehousing 14 of gas delivery device 12 by way of a interfitting lugarrangement. More particularly, as best seen in FIGS. 3 and 4, thegenerally cylindrical housing 50 of gas conditioning unit 30 includes aplurality of circumferentially spaced apart engagement lugs, includingan L-shaped lug 52 and a square-shaped lug 54. A third lug 56 can beseen in FIG. 8. The three engagement lugs 52, 54 and 56 are dimensionedand configured to interact with correspondingly shaped and positionedrecesses 62, 64 and 66 defined in the periphery of the cartridgeengagement port 60 formed in the front panel of housing 14, as shown inFIG. 2.

With continuing reference to FIGS. 3 and 4, the housing 50 of gasconditioning unit 30 includes a front end cap or cover 70 and a rear endcap or cover 90. The front end cap 70 has two conduit connection tubesassociated therewith. These include a first or central conduitconnection tube 72 that extends through an aperture 75 in the front endcap 70 and is operatively associated with the first conduit 32, shown inFIGS. 1 and 2. Front end cap 70 also includes a second conduitconnection tube 80 operatively associated with the second conduit 40,which are also shown in FIGS. 1 and 2.

Referring to FIG. 4, the rear end cap 90 includes three outlet ports,each having an associated sealing ring. The first outlet port 92communicates with the first internal flow path (i.e., the pressure pathshown in FIG. 11) and ultimately with tube 72. The second outlet port 94communicates with the second internal flow path (i.e., thesense/insufflation path shown in FIG. 10) and ultimately with tube 80.The third outlet port 96 communicates with the third internal flow path(i.e., the vacuum path shown in FIG. 13).

The first outlet port 92 includes a first O-ring seal 102, the secondoutlet port 94 includes a second O-ring seal 104 and the third outletport 96 includes a third O-ring seal 106. The three O-rings seals 102,104 and 106 are seated and arranged in a co-planar manner on the rearend cap 90 to cooperate with corresponding features within the cartridgeengagement port 60 in the front panel of housing 14.

A similar co-planar arrangement of O-ring seals is disclosed in commonlyassigned U.S. Patent Application Publication 2012/0138523, which isincorporated herein by reference in its entirety. In addition, the rearend cap 90 includes a central exhaust port 108, which permits theentrainment of air into the recirculation flow under certain operatingconditions. This will be described in more detail hereinbelow.

Referring now to FIG. 5, there is illustrated the gas conditioning unit30 with each of the components parts thereof separated from thecylindrical housing 50 for ease of illustration. Also shown are certaininternal features of the housing 50 of conditioning unit 30. Startingthere, the housing 50 includes several internal cavities for supportingcomponents and/or defining gas/fluid flow passages. At the front end ofhousing 50, there is a vacuum chamber 110, which is located within thethird internal flow path (i.e., the vacuum path shown in FIG. 13).

The vacuum chamber 110 is dimensioned and configured to support acylindrical pleated filter element 120 (see also FIG. 7). The pleatedfilter element 120 is preferably made from a porous non-woven ormelt-blown filter media fabricated from a plastic material such aspolypropylene or the like. Filter element 120 has an offset bore 122 toaccommodate the passage of the central conduit connection tube 72therethrough, when the unit 30 is fully assembled.

As best seen in FIGS. 7 and 9, the housing 50 of gas conditioning unit30 further includes a reservoir chamber 130, which is also locatedwithin the third internal flow path, downstream from and in fluidcommunication with the vacuum chamber 110. More particularly, thereservoir chamber 130 communicates with the vacuum chamber 110 through afluid transfer port 132 formed in the internal wall 135 of housing 50.Any fluid or debris accidentally drawn into the housing 50 of the gasconditioning 30 unit (e.g., through conduit 32) by the suction of pump20 in gas delivery device 12 accumulates first within the vacuum chamber110 until it reaches the level of the transfer port 132, whereupon suchfluid enters into the reservoir chamber 130.

Referring to FIG. 9, prism shaped fluid level sensors 134 and 136 arearranged within the reservoir chamber 130 for detecting a predeterminedfluid level therein. The structure and function of the fluid levelsensors 134, 136, and the alarm set points and circuity associatedtherewith is described in greater detail in commonly assigned U.S.Patent Application Publication 2013/0231606, the disclosure of which isherein incorporated by reference in its entirety.

With continuing reference to FIG. 5 in conjunction with FIGS. 7 and 9,the housing 50 of gas conditioning unit 30 further includes a pressurechamber 140 located within the first internal flow path (i.e., thepressure path shown in FIG. 11). Pressure chamber 140 is dimensioned andconfigured to support a cylindrical pleated filter element 150 (see alsoFIG. 7). Pleated filter element 150 is preferably made from a porousnon-woven or melt-blown filter media fabricated from a plastic materialsuch as polypropylene or the like.

Filter element 150 has a central bore 152 to accommodate, among othercomponents, a cylindrical breathing tube 165. Breathing tube 165communicates with the central breathing port 108 in the rear end cap 90to facilitate the entrainment of ambient air into the system undercertain operating conditions. As best seen in FIGS. 5 and 7, an annularbarrier wall 160 separates and fluidly isolates the reservoir chamber130 from the pressure chamber 140. The barrier wall 160 is seated on anannular ledge 162 formed in the inner wall of the housing 50.

The housing 50 of gas conditioning unit 30 also includes a centralnozzle chamber 170 defined primarily by a cylindrical wall 172, which issurrounded by pleated filter 150. The central nozzle chamber 170communicates with the pressure chamber 140 through an internal deliveryport 174 (see FIGS. 5 and 11). The central nozzle chamber 170 supports atwo-part annular nozzle assembly 180, which is shown in a separatedcondition in FIG. 6. The annular nozzle assembly 180 is described ingreater detail in commonly assigned U.S. Pat. No. 8,795,223, which isherein incorporated by reference in its entirety.

In general, the annular nozzle assembly 180 includes upper and lowerring jet components 182 and 184, which are connected to one another by aset of circumferentially spaced apart cooperating lugs 182 a-182 d and184 a-184 d. The upper ring jet component 182 includes a central tubularportion 183 having a set of circumferentially spaced apart recessedareas 185 forming a set of spaced apart land areas 187. The lower ringjet component 184 includes a continuous seating surface 189 forintimately receiving the tubular portion 183 of upper ring jet component182.

When the two ring jet components 182, 184 are interfit together, anannular nozzle is formed between the land areas 187 of the tubularportion 183 and the continuous seating surface 189. When pressurized airis delivered from the pressure chamber 140, through the delivery port174, into the nozzle chamber 170, and then through the nozzle 180 formedby the intimate engagement of the tubular portion 183 and the continuousseating surface 189, a pressure barrier or working zone is createdwithin the housing 50 of conditioning unit 30 to prevent the egress ofinsufflation gas from the abdominal cavity of a patient by way ofconduit 32. This is best seen in FIG. 12.

The annular nozzle assembly 180 further includes a pair of axiallyspaced apart outer sealing rings 186 a, 186 b for sealingly isolatingthe nozzle assembly 180 within the central nozzle chamber 170, as bestseen in FIG. 7. The central nozzle chamber 170 of housing 50 includes achamber extension member 175 that has a proximal funnel portion 177 anda distal tubular portion 179. The funnel portion 177 has a plurality ofcircumferentially disposed spaced apart axial vanes or fins 190 locateddistal to the cylindrical jet set 182, 184. The vanes 190 are adaptedand configured to direct the flow of spent gas (i.e., pressurized gasthat has lost its momentum after being delivered from the jet set nozzleassembly 180) away from the working zone. The distal portion 179 extendsdownwardly from the nozzle chamber 170 to a reduced distal section 179 athat accommodates conduit 32.

The central nozzle chamber 170 communicates with the breathing tube 165,which is located proximal to the nozzle assembly 180. The breathing tube165 is open to atmosphere and permits the entrainment of air into therecirculation flow of the gas delivery system under certain operatingconditions. The breathing tube 165 includes a base portion 167 thatforms an end cap for the nozzle chamber 170.

Referring to FIGS. 8 and 9, the vacuum chamber 110 communicates withcentral nozzle chamber 170 through a plurality of circumferentiallyspaced apart gas transfer ports 192 which permit spent gas from thenozzle assembly 180 to return to the pump 20 for repressurization andcirculation, as explained in more detail below. This is caused bysuction created by pump 20. The gas transfer ports 192 are defined aboutthe periphery of the funnel portion 177 of chamber extension member 175.

Referring once again to FIG. 5, the housing 50 of the gas conditioningunit 30 also includes a diverter plate 210 which interacts with theoutlet cover 90 to define, among other features, a conditioning cavity212 therebetween. The conditioning cavity 212 forms part of the secondinternal flow path, communicates with port 94 in end cap 90, and isconfigured to support a planar filter element 220 made from a non-wovenmesh or the like for filtering insufflation gas delivered from the gassource 18. Diverter plate 210 also includes a central aperture 215 toaccommodate the passage of breathing tube 165.

Referring now to FIG. 10, during operation, insufflation gas isdelivered from the gas source 18 into the conditioning cavity 212through the port 94 in the rear end cap 90. The gas is conditioned orotherwise filtered as it passes through planar filter element 220. Thefiltered gas exists the conditioning cavity 212 through the crescentshaped side aperture 214 in diverter plate 210 and then flows into theinternal side flow passage 216 of housing 50. The insufflating gas thenexits from the housing 50 by way of conduit tube 80 in the front end cap70 for delivery to the patient 15 through flexible conduit 40.

This same pathway shown in FIG. 10 is used to periodically senseabdominal pressure. That is, the flow of insufflation gas from gassource 18 is intermittently turned off by a valve (not shown) located inthe housing 14 of gas delivery device 12. As a result, there areintervals of time in which there is no flow through the sensing path(e.g. through path 216 in housing 50). At such times, static pressurewithin the abdominal cavity can be measured by the gas delivery device12 by way of conduit 40. This pressure measurement is utilized to adjustthe flow of gas to the abdominal cavity, for example.

Referring now to FIG. 11, during operation, pressurized gas is deliveredfrom the pump 20 in gas delivery device 12 through the port 92 in therear end cap 90. The pressurized gas then passes through the centrallyoffset circular aperture 218 in diverter plate 210 and then into thepressure chamber 140, where it is conditioned or otherwise filtered bypassing through pleated filter element 150.

The pressurized gas then travels to the central nozzle chamber 170 byway of internal delivery port 174. In the central nozzle chamber 170,the pressurized gas is directed through the nozzle assembly 180 where itforms a pressure barrier within the upper region of central tubularpassage 280 of tubular portion 179 that is operatively associated withthe conduit tube 72, as best seen in FIG. 12. This pressure barrier orworking zone prohibits the egress of insufflation gas coming up from theabdominal cavity through flexible conduit 32 and conduit tube 72, whilemaintaining a stable pneumoperitoneum within the abdominal cavity of thepatient 15.

Referring to FIG. 13, during operation, the suction from pump assembly20 draws the spent fluid/gas that had been used to develop the pressurebarrier within the conditioning unit through the plural apertures 192 ofthe nozzle chamber 170. That spent fluid/gas enters into the vacuumchamber 110, flows through the side port 282 and into the lateral flowpath 284. The spent fluid/gas then exits the housing 50 through exitport 96 and returns to pump 20. The conditioned flow is repressurized bythe pump 20 and recirculated back to the housing 50 through pressureaperture 92 for subsequent delivery to the nozzle assembly 180 in nozzlechamber 170.

While the gas delivery device and associated gas conditioning unit ofthe subject invention have been shown and described with reference to apreferred embodiment, those skilled in the art will readily appreciatethat various changes and/or modifications may be made thereto withoutdeparting from the spirit and scope of the subject invention as definedby the appended claims. For example, the locations and relativepositions of each of the gas flow paths formed within the conditioningunit could vary, and the type and size of the filter elements usedwithin the conditioning unit could also vary.

What is claimed is:
 1. A system for delivering gas during a laparoscopicsurgical procedure performed within a patient's abdominal cavity,comprising: a) a gas delivery device having a housing with a port forreceiving insufflation gas from a gas source, the housing of the gasdelivery device being configured for enclosing a pump assembly forcirculating gas throughout the system; and b) a separate gasconditioning unit having a housing configured for operative associationwith the gas delivery device and including: i) a first internal flowpath for delivering pressurized gas delivered from the pump assembly toan internal nozzle assembly that is located within the housing of thegas conditioning unit and is configured to accelerate the pressurizedgas and thereby generate a continuous pressure barrier contained withinthe gas conditioning unit that inhibits egress of insufflation gas fromthe abdominal cavity; ii) a second internal flow path for deliveringinsufflation gas to the abdominal cavity and for facilitating periodicstatic pressure measurements from the abdominal cavity; and iii) a thirdinternal flow path for returning depressurized gas spent by the internalnozzle assembly back to the pump assembly under vacuum, wherein thehousing of the gas conditioning unit is generally cylindrical andincludes a front end and an opposed rear end, and wherein the housing ofthe gas delivery device includes an engagement port for detachablyreceiving the rear end of the housing of the gas conditioning unit, andwherein the rear end of the housing of the gas conditioning unitincludes a rear cover having a first rear flow port corresponding to thefirst internal flow path, a second rear flow port corresponding to thesecond internal flow path, and a third rear flow port corresponding tothe third internal flow path.
 2. A system as recited in claim 1, whereinthe front end of the gas conditioning unit includes a front cover havinga first front flow port corresponding to the first internal flow pathwhich communicates with a first conduit, and a second front flow portcorresponding to the second internal flow path which communicates with asecond conduit.
 3. A system as recited in claim 2, wherein the firstconduit includes a fitting for communicating with a first surgicalaccess port, and wherein the first surgical access port includes amechanical valve associated with a central lumen thereof foraccommodating the introduction of surgical instruments into theabdominal cavity.
 4. A system as recited in claim 2, wherein the secondconduit includes a fitting for communicating with a second surgicalaccess port responsible for insufflation and pressure measurement of theabdominal cavity.
 5. A system as recited in claim 1, wherein the housingof the gas conditioning unit includes an internal pressure chamberlocated within the first internal flow path and communicating with afirst rear flow port.
 6. A system as recited in claim 5, wherein thehousing of the gas conditioning unit includes an internal central nozzlechamber having a cylindrical wall supporting the internal nozzleassembly, and wherein the internal central nozzle chamber communicateswith the internal pressure chamber through an internal delivery port. 7.A system as recited in claim 6, wherein the internal nozzle assemblyincludes a cylindrical jet set having a pair of axially spaced apartouter sealing rings for sealingly isolating the internal nozzle assemblywithin the internal central nozzle chamber.
 8. A system as recited inclaim 7, wherein the internal central nozzle chamber includes aplurality of circumferentially disposed spaced apart axial fins distalto the cylindrical jet set for directing gas flow.
 9. A system asrecited in claim 7, wherein the internal central nozzle chambercommunicates with a breathing tube proximal to the cylindrical jet setthat is open to atmosphere.
 10. A system as recited in claim 6, whereinthe housing of the gas conditioning unit includes an internal vacuumchamber located within the third internal flow path.
 11. A system asrecited in claim 10, wherein the internal vacuum chamber communicateswith the internal nozzle chamber through a plurality of gas transferports to permit spent gas from the internal nozzle assembly to return tothe pump assembly for repressurization and circulation.
 12. A system asrecited in claim 10, wherein a third filter element is disposed withinthe internal vacuum chamber for filtering depressurized gas returning tothe pump assembly.
 13. A system as recited in claim 10, wherein thehousing of the gas conditioning unit further includes an internalreservoir chamber located within the third internal flow path,downstream from and in fluid communication with the internal vacuumchamber through a fluid transfer port, for accommodating any fluid drawninto the housing of the gas conditioning unit by the pump assembly. 14.A system as recited in claim 13, wherein a fluid level sensor isarranged within the internal reservoir for detecting a predeterminedfluid level therein.
 15. A system as recited in claim 5, wherein a firstfilter element is disposed within the internal pressure chamber forfiltering pressurized gas from the pump assembly.
 16. A system asrecited in claim 1, wherein the housing of the gas conditioning unitincludes a diverter plate which interacts with the rear cover to definea conditioning cavity disposed in the second internal flow path andconfigured to support a second filter element for filtering insufflationgas from the gas source.
 17. A gas conditioning unit for use with a gasdelivery device during a laparoscopic surgical procedure performedwithin a patient's abdominal cavity, comprising: a) a housing having arear end configured for engagement with the gas delivery device and anopposed front end; b) a first filtered flow path within the housing fordelivering pressurized gas delivered from a pump located within the gasdelivery device to an internal annular nozzle assembly that is locatedwithin the housing of the gas conditioning unit and is configured toaccelerate the pressurized gas and thereby generate a continuouspressure barrier contained within the gas conditioning unit thatinhibits egress of insufflation gas from the abdominal cavity; c) asecond internal flow path for delivering insufflation gas to theabdominal cavity and for facilitating periodic static pressuremeasurements from the abdominal cavity; and d) a third internal flowpath for returning depressurized gas spent by the internal nozzleassembly back to the pump under vacuum, wherein the rear end of thehousing of the gas conditioning unit includes a rear cover having afirst rear flow port corresponding to the first filtered flow path, asecond rear flow port corresponding to the second filtered flow path anda third internal rear flow port corresponding to the third internalfiltered flow path.
 18. A gas conditioning unit as recited in claim 17,wherein the front end of the housing of the gas conditioning unitincludes an front cover having a first front flow port corresponding tothe first filtered flow path which communicates with the first conduit,and a second front flow port corresponding to the second filtered flowpath which communicates with the second conduit.
 19. A gas conditioningunit as recited in claim 18, wherein the housing of the gas conditioningunit includes an internal pressure chamber located within the first flowpath and communicating with the first rear flow port.
 20. A gasconditioning unit as recited in claim 19, wherein the housing of the gasconditioning unit includes an internal central nozzle chamber having acylindrical wall supporting the internal annular nozzle assembly, andwherein the internal central nozzle chamber communicates with theinternal pressure chamber through an internal delivery port.
 21. A gasconditioning unit as recited in claim 20, wherein the internal annularnozzle assembly includes a cylindrical jet set having a pair of axiallyspaced apart outer sealing rings for sealingly isolating the internalnozzle assembly within the internal central nozzle chamber.
 22. A gasconditioning unit as recited in claim 21, wherein the internal centralnozzle chamber includes a plurality of circumferentially disposed spacedapart axial fins distal to the cylindrical jet set for directing gasflow.
 23. A gas conditioning unit as recited in claim 22, wherein theinternal central nozzle chamber communicates with a breathing tubeproximal to the cylindrical jet set that is open to atmosphere.
 24. Agas conditioning unit as recited in claim 23, wherein a first filterelement is disposed within the internal pressure chamber for filteringpressurized gas from the pump.
 25. A gas conditioning unit as recited inclaim 24, wherein the housing of the gas conditioning unit includes adiverter plate which interacts with the rear cover to define aconditioning cavity disposed in the second filtered flow path andconfigured to support a second filter element for filtering insufflationgas from the gas source.
 26. A gas conditioning unit as recited in claim25, wherein the housing of the gas conditioning unit includes aninternal vacuum chamber located within the third filtered gas path. 27.A gas conditioning unit as recited in claim 26, wherein the internalvacuum chamber communicates with the internal nozzle chamber through aplurality of gas transfer ports to permit spent gas from the internalnozzle assembly to return to the pump for repressurization andcirculation.
 28. A gas conditioning unit as recited in claim 27, whereina third filter element is disposed within the internal vacuum chamberfor filtering gas returning to the pump.
 29. A gas conditioning unit asrecited in claim 28, wherein the housing of the gas conditioning unitfurther includes an internal reservoir chamber located within the thirdfiltered flow path, downstream from and in fluid communication with theinternal vacuum chamber through a fluid transfer port, for accommodatingany fluid drawn into the housing of the gas conditioning unit by thepump.
 30. A gas conditioning unit as recited in claim 29, wherein afluid level sensor is arranged within the internal reservoir fordetecting a predetermined fluid level therein.
 31. A gas conditioningunit as recited in claim 18, wherein the first conduit includes afitting for communicating with a first surgical access port, and whereinthe first surgical access port includes a mechanical valve associatedwith a central lumen thereof for accommodating the introduction ofsurgical instruments into the abdominal cavity.
 32. A gas conditioningunit as recited in claim 18, wherein the second conduit includes afitting for communicating with a second surgical access port responsiblefor insufflation and pressure measurement of the abdominal cavity.